1. Field of the Invention
The present invention relates to a light emitting diode package structure, and particularly relates to a structure for electrically connecting a light emitting diode to an external unit via a flexible PCB.
2. Description of Related Art
Compact electrical devices typified by mobile devices such as recent digital still cameras and mobile phones, often employ a flexible print circuit board (hereafter referred to as “FPCB”) as substrates for electrical connection between units or circuits for reduction in size and weight. Relatively small and light components such as chip components are sometimes directly soldered on FPCBs. For soldering an LED on an FPCB, a surface mount LED is generally used from a viewpoint of easiness of size reduction and assembling.
FIG. 8 shows one example of a surface mount light emitting diode package 80 having such a conventional structure. FIG. 8 illustrates a light emitting diode (LED) 82, which comprises a light emitting element (LED chip), a wire (gold wire) for electrical connection to the light emitting element, a conductive resin for conduction of an electrode at the bottom surface of the light emitting element (components mentioned heretofore being not shown), a lead frame 85, a transparent encapsulation resin 83 such as an epoxy resin serving as a lens, and a flange 84. There are provided soldering 86 for electrical connection between the lead frame 85 and a conductive pad of an FPCB 87, and a rigid PCB 88.
As shown in FIG. 8, the LED 82 is mounted on the FPCB 87 by soldering the lead frame 85 to the FPCB 87. The rigid PCB 88 as a rigid body is attached to a rear surface of the FPCB 87 as a support for the soldering. Further, when the light emitting diode package is pressed at its rear surface by a leaf spring to securely hold the light emitting diode package in a unit, the rigid PCB is required to provide a hard flat surface for contact with the leaf spring.
Other conventional structures using lead frames are disclosed in Japanese Patent Laid-open Publications 2001-177,160 (FIG. 10) and H9-83,018 (FIG. 1).